Posted on April 26, 2012 by Anthony Watts From the Harvard School of Engineering and Applied Sciences“Warming hole” delayed climate change over eastern United StatesApril 26, 201250-year model suggests regional pollution obscured a global trend CONTACT: Caroline Perry, (617) 496-1351 Cambridge, Mass. – April 26, 2012 – Climate scientists at the Harvard School of Engineering and Applied Sciences (SEAS) have discovered that particulate pollution in the late 20th century created a “warming hole” over the eastern United States—that is, a cold patch where the effects of global warming were temporarily obscured.While greenhouse gases like carbon dioxide and methane warm the...

While greenhouse gases like carbon dioxide and methane warm the Earth's surface, tiny particles in the air can have the reverse effect on regional scales. "What we've shown is that particulate pollution over the eastern United States has delayed the warming that we would expect to see from increasing greenhouse gases," says lead author Eric Leibensperger (Ph.D. '11), who completed the work as a graduate student in applied physics at SEAS. "For the sake of protecting human health and reducing acid rain, we've now cut the emissions that lead to particulate pollution," he adds, "but these cuts have caused the...